Unified frame for semiconductor material handling system

ABSTRACT

The present invention is a unified spine structure that EFEM components, such as a wafer handling robot and a SMIF pod advance assembly, may mount to. The frame includes multiple vertical struts that are mounted to an upper support member and a lower support member. Structurally tying the vertical struts to the support members creates a rigid body to support the EFEM components. The vertical struts also provide a common reference that the EFEM components may align with. This eliminates the need for each EFEM component to align with respect to each other. Thus, if one EFEM component is removed it will not affect the alignment and calibration of the remaining secured EFEM components. The unified frame also creates an isolated storage area for the SMIF pod door and the port door within the environment that is isolated from the outside ambient conditions.

CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. §120 to U.S. patentapplication Ser. No. 10/087,638, entitled “Unified Frame forSemiconductor Material Handling System,” filed with the U.S. Patent &Trademark Office on Mar. 1, 2002, which claims priority to U.S.Provisional Patent Application No. 60/316,722, filed Aug. 31, 2001, nowabandoned, and both incorporated herein by reference.

CROSS-REFERENCE TO RELATED APPLICATIONS

1. U.S. patent application Ser. No. 10/087,400, entitled “WAFER ENGINE,”filed with the U.S. Patent & Trademark Office on Mar. 1, 2002; and

2. U.S. patent application Ser. No. 10/087,092, entitled “SEMICONDUCTORMATERIAL HANDLING SYSTEM,” filed with the U.S. Patent & Trademark Officeon Mar. 1, 2002; and

3.U.S. patent application Ser. No. 10/234,640, entitled “UniversalModular Wafer Transport System,” filed with the U.S. Patent & TrademarkOffice on Sep. 3, 2002.

FIELD OF THE INVENTION

The present invention generally relates to a frame for a workpiecehandling system. More particularly, the present invention comprises amodular frame or structure of a semiconductor material handling system.

BACKGROUND OF THE INVENTION

Standard Mechanical Interface Pods (SMIF pods) are in general comprisedof a pod door which mates with a pod shell to provide a sealedenvironment in which wafers may be stored and transferred. One type ofpod is a front opening unified pod, referred to as FOUP 10, in which thepod door is located in a vertical plane, and the wafers are supportedeither in a cassette mounted within the pod shell, or two shells mountedin the pod shell.

During the fabrication of semiconductor wafers, the SMIF pods are usedto transport the workpieces between various tools in the wafer fab.These tools include process tools for forming integrated circuitpatterns on the wafers, metrology tools for testing the wafers, sortersfor sorting and rearranging the wafers within one or more SMIF pods, andstockers for large scale storage of SMIF pods. The tools are generallylaid out in a wafer fab in one of two configurations, a bay and a chaseconfiguration or a ballroom configuration. In the former arrangement,only the front of the tool including the workpiece I/O port ismaintained in the clean room environment of Class-1 or better. In theballroom configuration, the tools are arranged in clusters according tothe operations they perform, with the entire tool being maintained inthe clean room environment of Class-1 or better.

Tools within a wafer fab include a front-end interface which housescomponents that facilitate and monitor the transfer of workpieces (i.e.wafers) between the pods to the tools. A conventional front end unit orequipment front end module (EFEM) 20 is shown in FIGS. 1-2. EFEMs 20 aregenerally constructed at a tool manufacturer and then shipped to a waferfab.

An EFEM 20 generally includes a housing 22 which is fixed to the frontof the tool and a workpiece handling robot 24 mounted within the housingand is capable of x, r, θ, Z motion to transfer workpieces between theworkpiece carriers, tool and other front end components. The robot 24 isgenerally mounted with leveling screws that will allow the adjustment ofthe planarity of the robot 24 once the EFEM 20 is constructed andaffixed to a tool.

In addition to a robot 24, the EFEM 20 generally includes one or moreprealigners 26 for performing the operation of wafer centeridentification, notch orientation, and indocile mark reading. Theprealigner(s) 26 are commonly bolted into the housing 22 with levelingscrews allowing the planarity of the prealigner(s) to be adjusted oncethe EFEM 20 is constructed and affixed to a tool.

An EFEM 20 further includes one or more load port assemblies 28 forreceiving a workpiece carrier, opening the carrier, and presenting theworkpiece to the robot 24 for transfer of the workpieces between thecarrier, and other processing tools. For 300 mm wafer processing, avertically oriented frame, commonly referred to as a Box Opener-LoaderTool Standard Interface (or “BOLTS” interface), has been developed bySemiconductor Equipment and Materials International (“SEMI”). The BOLTSinterface attaches to, or is formed as part of, the front end of a tool,and provides standard mounting points for the load port assembly toattach to the tool. U.S. Pat. No. 6,138,721, entitled “Tilt and Go LoadPort Interface Alignment System,” which is assigned to the owner of thepresent application and which is incorporated by reference in itsentirety herein, discloses a system for adjusting a load port assemblyto the proper position adjacent a BOLTS interface and then affixing theload port assembly to the interface.

Once the robot 24, the prealigners 26 and load port assemblies 28 havebeen mounted to the housing 22, the EFEM 20 is shipped to the wafer faband affixed to a tool within the fab. After being properly secured tothe tool, the EFEM components are leveled within the housing 22 via theleveling screws, and the robot 24 is then taught the acquisition anddrop-off positions it will need to access for workpiece transfer betweenthe load port assemblies, the prealigners and the tool. A system forteaching the various acquisition and drop-off positions for the robotwithin the tool front end is disclosed in U.S. patent application Ser.No. 09/729,463, entitled “Self Teaching Robot,” which application isassigned to the owner of the present application and which applicationis incorporated by reference herein in its entirety. Once the robotpositions have been taught, side panels are attached to housing 22 tosubstantially seal the housing against the surrounding environment.

For example, conventional EFEMs include many separate and independentworkpiece handling components mounted within an assembled housing. Thehousing 22 includes a structural frame, bolted, constructed or weldedtogether, in a plurality of panels affixed to the frame. After thehousing 22 is assembled, the EFEM components are fixed to the variouspanels. It is a disadvantage to prior art EFEMs that the overall systemtolerances are compounded with each frame member, panel and componentconnection. The result is that the assembled EFEM components are poorlyaligned and need to be adjusted to the proper position with respect toeach other. The robot 24 must also be taught the relative positions ofthe components so that the EFEM components can interact with each other.This alignment and teaching process must take place every time there isan adjustment to one or more of the EFEM components.

A further shortcoming of the prior art is that EFEM components arefrequently made by different suppliers, each with its own controller andcommunication protocols. Steps must be taken upon assembly of the EFEMso that the controllers of each component can communicate with eachother and the components can interact with each other. The separatecontrollers also complicate maintenance and add to the parts andelectrical connections provided in the EFEM. Further still, especiallyin a ballroom configuration, the conventional EFEM takes up a largeamount of space within a Class-1 cleanroom environment where space is ata premium.

Today's 300 mm semiconductor EFEMs are comprised of several majorsubsystems including SEMI E15.1 compliant load port modules (typically2-4 per tool). For example, an EFEM may consist of a wafer handlingrobot and a fan filter unit mounted to a structural steel frame, andhave panels to enclose the wafer handling area between the load portsand the process tool. The combination of these components provides ameans of transferring wafers to and from a FOUP 10, and between the FOUPand the process tool wafer dock(s). FOUPs 10 are manually loaded viaoperators or automatically loaded via an automated material handlingsystem (AMHS) delivered to and taken from the Load Port. IndustryStandards have been created to allow multiple vendors to provide theLoad Port, FOUP 10, or other EFEM components to be integrated as asystem.

The Load Port component provides a standard interface between the AMHSand the wafer handling robot in the EFEM. It provides a standardizedlocation to set the FOUP 10, docks the FOUP 10 to seal the frontsurface, and opens and closes the door to allow access to the wafers inthe FOUP 10. The dimensions of this unit are all specified in SEMIE15.1.

The Load Port attaches to the Front End via the Bolts Interface which isdefined by SEMI E-63. This standard defines a surface and mounting holesto which the Load Port attaches. It is defined to start at the fab floorand goes as high as 1386 mm from the floor and is about 505 mm wide perLoad Port. As a result, the load port completely blocks off the processtool from the operator aisle in the fab. SEMI E-63 also defines loadport dimensions on the tool side to ensure interchangeability with avariety of robot manufacturers.

The primary functions of the load port include accepting a FOUP 10 fromand presenting to a FOUP 10 to the Fab AMHS, moving the FOUP 10 towardsand away from the port seal surface (docking/undocking), and opening andclosing the FOUP door. In addition, it must perform functions such aslocking the FOUP 10 to the advance plate, lock and unlock the FOUP door,and a variety of lot ID and communication functions. Per SEMI E15.1, allof these functions are contained in a single monolithic assembly whichis typically added or removed from the tool front end as a completeunit.

The load port must be aligned with precision to the wafer robot. Ifthere are multiple load ports in the system, they must all present thewafers in level parallel planes. Typically, the Load Ports provideseveral adjustments to planarize the wafer in the FOUP 10 with therobot. In order to minimize time spent calibrating the robot to each ofthe 25 wafer positions in each of the FOUPs 10, specialized tools andalignment fixtures are used in conjunction with all of the adjustments.If a load port is swapped out with a new one, the calibration procedurecan be quite lengthy.

In addition to aligning the robot to the wafers positions, the doormechanism must also be aligned with the door opening and the door sealframe. Again, this is typically performed with alignment fixtures andtools either on the tool front end or off line.

The robot must also be leveled and aligned with one or more tool dropoff point. This is typically done manually by teaching the robot theposition and making planarity adjustments either on the front end or thetool.

It is the combination of all of these relationships between the tool,the robot, and the FOUPs 10 which make setting up a tool front end sotime consuming. All of the components are typically attached to arelatively low precision frame, and adjustments are used to compensatefor it. The load ports are mounted to the front surface, the robot tothe base, the fan/filter unit (FFU) to the top, and skins on all otheropen surfaces to complete the mini-environment enclosure.

It would be advantageous to minimize the adjustments between thecomponents and reduce the overall time required to align the load port.The present invention provides such an advantage.

SUMMARY OF THE INVENTION

One aspect of the present invention is to provide a unified structure orframe that precisely ties many critical EFEM components together. In oneembodiment, the frame serves as a single reference for aligning theinterior and exterior EFEM components. In another embodiment, theinterior and exterior EFEM components are aligned in relation to eachvertical strut of the frame.

Another aspect of the present invention is to provide a unifiedstructure or frame that is scalable in size. In one embodiment, theunified structure includes vertical struts secured to an upper and lowersupport member. The number of vertical struts and the length of theupper and lower support member depends on the number of I/O ports withinthe EFEM. Similarly, the size and spacing of the vertical struts and thesupport members may vary to accommodate 200 mm wafers, 300 mm wafers,and 400 mm wafers.

Yet another aspect of the present invention is to accurately andprecisely locate the front load components with respect to each other.Preferably, this calibration process is accomplished with a minimumnumber of adjustments. In one embodiment, all the interior and exteriorEFEM components are precisely tied to the unified frame such that theyshare common reference points.

Yet another aspect of the present invention is to provide a unifiedframe that segregates and isolates the port door/carrier door assemblyfrom the many of the interior EFEM components. In one embodiment, theport door/carrier door assembly is lowered into a separate airflow/storage area located within the mini-environment. The storage areaprevents particles created by, for example, a wafer handling robot, fromcontaminating the assembly.

Still another aspect of the present invention is to provide a wafercarrier docking/interface plate that can be easily removed from the EFEMto access the interior of the EFEM. In one embodiment of the presentinvention, the removable plate is manufactured from a transparentmaterial so that a user may observe any problems/malfunctions that occurwithin the mini-environment.

Still another aspect of the present invention is to decrease thefootprint of the EFEM. In one embodiment, the EFEM is supported by arolling stand whereby the bottom surface of the EFEM is raised off thefloor of the wafer fab. The area between the wafer fab floor and theEFEM may serve as a maintenance access port to the processing tool, oran area to place auxiliary compartments.

Still another aspect of the present invention is to provide a waferengine for transferring wafers. In one embodiment, the wafer engine mayperform a number of inspection, marking, and metrology functions,eliminating the need for a separate processing station.

Still another aspect of the present invention is to provide a waferengine that may transfer wafers within the reduced footprint of theEFEM. In one embodiment, a wafer engine includes a linear drive formoving the wafer along a x-axis, a vertical drive for moving the waferz-axis, a radial drive for moving the wafer along a radial axis, and arotational drive for rotating the vertical and radial drive about atheta axis.

A further aspect of the present invention is to provide local filteringfor various particle generating mechanisms on the wafer engine. In oneembodiment, a fan/filter unit is mounted to the radial drive to captureparticles created by the radial drive. In another embodiment, an exhaustsystem creates an air flow through the vertical drive to capture anyparticles created by the vertical drive. These localized fan/filterunits attempt to control particles created by the wafer engine byexhausting the particles into a “dirty-air” environment, or by firstfiltering the air before it is exhausted back into a “clean air”environment.

Still another aspect of the present invention is to provide a waferengine that has dual swap and align-on-the-fly capabilities. In oneembodiment, the wafer engine has a rapid swap radial drive, or buffercapability, to simultaneously store and transfer two wafers. In anotherembodiment, an upper end effector may rotate and align a first waferwhile a second wafer is stored and/or transported by a lower endeffector.

Still another aspect of the present invention is to provide a waferengine that has a removable/interchangeable slide body mechanism. In oneembodiment, the slide body mechanism includes integrated processingtools such as an OCR reader, an aligner, an ID reader, or a metrologytool. A removable slide body mechanism allows a wafer fab to incorporatethe same wafer engine throughout whereby only the slide body mechanismmust be customized to each individual process station.

Yet another aspect of the present invention is to provide a wafer enginehaving a vertical drive located above the theta drive. Such a verticaldrive is located substantially within the FOUP 10 area and minimizes thefootprint of the wafer engine.

The present invention provides all of these advantages.

DETAILED DRAWINGS OF THE PRESENT INVENTION

FIG. 1 is a perspective view of a conventional front end assembly inaccordance with the prior art;

FIG. 2 is a top view of the front end assembly shown in FIG. 1;

FIG. 3 is a side view of a conventional front end assembly in accordancewith the prior art;

FIG. 4 is a perspective view of an embodiment of the spine structure,according to the present invention;

FIG. 5 is a partial exploded view of the spine structure shown in FIG.4;

FIG. 6 is a perspective view of an embodiment of a FOUP dockinginterface, according to the present invention;

FIG. 7 is a partial exploded perspective view of an embodiment of thespine structure and front end load components, according to the presentinvention;

FIG. 8 is a perspective view of an embodiment of a wafer engine mountedto the spine structure, according to the present invention;

FIG. 9 is a perspective view of an embodiment of a wafer engine driverail mounted to the spine structure, according to the present invention;

FIG. 10 is a side view of an embodiment of the front end load interface,according to the present invention;

FIG. 11 is a partial exploded view of another embodiment of theintegrated mini-environment and structure, according to the presentinvention;

FIG. 12 is a side view of the integrated mini-environment and structureas shown in FIG. 11;

FIG. 13 is a partial perspective view of an embodiment of the backbonestructure according to the present invention;

FIG. 14 is perspective view of still another embodiment of theintegrated mini-environment and structure, according to the presentinvention;

FIG. 15 is an end view of the integrated mini-environment and structureshown in FIG. 14;

FIG. 16 is a partial exploded view illustrating an embodiment of theunitized frame of the integrated mini-environment and structure shown inFIG. 15;

FIGS. 17A-17B; FIG. 17A is a top view of an embodiment of a conventionalwafer handling robot; FIG. 17B is a top view of the wafer handling robotshown in FIG. 17A with the end effector extended, according to the priorart;

FIG. 18 is a perspective view of an embodiment of a rapid swap waferengine, according to the present invention;

FIG. 19 is a perspective view of the wafer engine shown in FIG. 18illustrating several of the components of the drive mechanisms and thevertical column and the slide body mechanism;

FIG. 20 is a perspective view of another embodiment of a wafer engine,according to the present invention;

FIG. 21 is a perspective view of the wafer engine shown in FIG. 18,illustrating the air flows created by the fan/filter units;

FIGS. 22A-22D; FIG. 22A is a perspective view of still anotherembodiment of a wafer engine equipped with a wheeled aligner and an IDreader on the slide body mechanism, according to the present invention;FIG. 22B is a top view of the wafer engine shown in FIG. 22A; FIG. 22Cis a slide view of the wafer engine shown in FIG. 22A; FIG. 22D is arear view of the wafer engine shown in FIG. 22A;

FIG. 23 is a perspective view of an embodiment of the upper end effectorshown in FIG. 22A;

FIGS. 24A-24C; FIG. 24A is a cut away view of an embodiment of thewheeled end effector aligner illustrating a wafer supported by the pad;FIG. 24B is cut away view of the wheeled end effector aligner in FIG.24A illustrating the wafer lifted off the pad and supported by thewheel; FIG. 24C is cut away view of the wheeled end effector alignershown in FIG. 24 A illustrating the wafer being released by the wheeland set back down on the pad;

FIG. 25 is a perspective view of yet another embodiment of the waferengine, according to the present invention;

FIG. 26A-26B; FIG. 26A is a perspective view of another embodiment ofthe radial drive; FIG. 26B is still another embodiment of the radialdrive;

FIGS. 27A-27B; FIG. 27A is a plan view illustrating the reach and swingclearance advantage of the wafer engine according to the presentinvention; FIG. 27B is plan view of a conventional linear slide robotillustrating the minimum clearance and maximum reach required;

FIG. 28 illustrates an example motion sequence for the rapid swap slidebody with off center rotation axis, according to the present invention;

FIGS. 29A-29D; FIG. 29A is a perspective view of an embodiment of thefront end load interface, according to the present invention; FIG. 29Bis a front view of the integrated system shown in FIG. 29A; FIG. 29C isa side view of an embodiment of the front end load interface shown inFIG. 29A; FIG. 29D is a plan view of an embodiment of the front end loadinterface shown in FIG. 29A;

FIGS. 30A-30B; FIG. 30A is a perspective view of an embodiment of theintegrated system mounted to a processing tool; FIG. 30B is a side viewof the integrated system shown in FIG. 30A; and

FIG. 31 is a side view of the integrated system shown in FIGS. 30A-30B,illustrating how the integrated system frees up space for AutomatedMaterial Handling System (AMHS) buffering.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention will now be described with reference to FIGS.4-31, which relate generally to a wafer transfer system. The preferredembodiments of the present invention are used for 300 mm semiconductorwafer fabrication. The present invention may also be used in thefabrication of workpieces other than semiconductor wafers, such as forexample reticles, flat paneled displays and magnetic storage disks. Thepresent invention may also be used in the fabrication of workpieceslarger or smaller than 300 mm, such as for example 200 mm and 150 mm.Moreover, while the present invention preferably operates within a FOUPsystem, it is understood that the present invention may operate withother workpiece transport systems, including open wafer cassettesystems.

Unified Spine Structure

The spine structure 100 is based off the idea that a single unifiedframe or structure may serve as a base foundation for an EFEM. Thisfoundation may be repeatedly manufactured in a similar fashion so as tolower the cost of the system, and allow EFEM components to mount to theframe to simplify alignment. The structure or frame 100 minimizes theamount of space required by a front end load tool. A frame or structurealso minimizes alignment time and greatly simplifies access tocomponents located inside the front end tool for maintenance proceduresand/or services that are required.

FIGS. 4-5 illustrate a preferred embodiment of the unified spinestructure 100. The spine 100 includes multiple vertical struts 102 thatare connected together by an upper channel or support member 104 and alower channel or support member 106. Each vertical strut 102 has aninward face 108 and an outward face 110. As shown throughout FIGS. 4-10,each vertical strut 102 preferably has a substantially rectangularcross-section. A rectangular cross section is preferred so that theoutward face 110 of each vertical strut 102 forms a seal with any EFEMcomponent mounted to the vertical strut 102. The rectangularcross-section of each vertical strut 102 also ensures that the uppersupport member 104 and lower support member 106 are flush against theinward face 108 and outward face 110 when secured to each vertical strut102. It is within the scope and spirit of the invention for the verticalstrut 102 to have a different cross section such as, but not limited to,circular or oval.

In the preferred embodiment, the spine structure 100 is comprisedprimarily of sheet metal components, with a few machine components wherethe precision is required. The sheet metal is implemented in ways whichtake advantage of the precision that can be derived from some aspects ofthis fabrication technique. For example, the long bends in the uppersupport member 104 and lower support member 106 that form a “U”-shapeprovide a very straight reference to align the vertical struts 102. In apreferred embodiment, holes 120 and 122 are punched in the upper andlower channel 104 and 106 to further guarantee good hole to holealignment between each vertical strut 102 and the upper and lowerchannel 104 and 106.

The sheet metal components also serve the function of exterior skins ormounting surfaces (described hereinafter) to the system as well asstructural support. In current EFEM systems, sheet metal is usuallyreserved for non-structural panels which only provide cosmetic finishand containment. By incorporating sheet metal into several of thestructural components, the material cost of the EFEM may be dramaticallyreduced.

The upper support member 104 is secured to the top portion 114 of eachvertical strut 102, while the lower support member 106 is secured to thebottom portion 112 of each vertical strut 102. Accordingly, the spine100 provides a very straight and stiff structure in both torsion andbending to build a front end load system on. In a preferred embodiment,the upper support member 104 and the lower support member 106 aremanufactured from a single piece of sheet metal. The bends in the sheetmetal to create the upper support member 104 are dictated by the widthof the upper portion 114 of each vertical strut 102, so that the widthof the “U”-shaped upper support member 104 is substantially similar tothe width of the upper portion 114 of each vertical strut 102.Similarly, the width of the lower “U”-shaped support member 106 ispreferably substantially similar to the width of the bottom portion 112of each vertical strut 102. Each support member 104 and 106 is intendedto be flush against the inward face 108 and outward face 110 of eachvertical strut 102.

In a preferred embodiment, the lower portion 112 of each vertical strut102 is wider than the upper portion 114 of each vertical strut 102. Asbest shown in FIGS. 4-5, the spine structure 100 aligns each verticalstrut 102 in a vertical orientation so that each vertical strut 102 issubstantially parallel to each other. Each strut 102 is preferablyspaced on 505 mm centers, which is the minimum allowed spacing foradjacent load ports per SEMI E-15.1. It is within the scope and spiritof the invention for the vertical struts 102 to be spaced apart atvarious or unequal distances.

To provide a rigid structure in both a torsional and lateral direction,each vertical strut 102 is secured to both the upper support member 104and the lower support member 106. Each vertical strut 102 is positionedbetween the upper support member 104 and lower support member 106 asshown in FIG. 4. As previously described, each vertical strut 102 isaligned with the mounting holes 120 and 122 in the upper support member104 and the lower support member 106. By way of example only, eachvertical strut 102 is secured to the upper support member 104 by a boltor pin secured to the top portion 114 of the vertical strut 102 (e.g.through mounting hole 120), and at least one bolt or pin secured to thefront face 110 or the back face 108. Each vertical strut 102 must alsobe secured to the lower support member 106. By way of example only, abolt or pin is secured to the bottom portion 112 of each vertical strut102 (e.g. through mounting hole 122), and at least one bolt or pin issecured to both the front face 110 and the rear face 108.

The “U”-shaped configuration of the upper support member 104 and thelower support member 106 further prevent each vertical strut 102 fromrotating in place. Although the upper channel 104 and lower channel 106as shown in FIGS. 4-5 are manufactured from a single piece of sheetmetal, it is within the scope and spirit of the invention for the uppersupport member 104 and lower support member 106 to be manufactured frommultiple pieces of material. In a preferred embodiment, and as bestshown in FIG. 5, the upper support member 104 and lower support member106 have a perforated surface. The perforated surfaces of the uppersupport member 104 and lower support member 106 allow air from afan/filter unit 150 (FFU) to flow through (see FIG. 10).

When the lower support member 106 is secured to the vertical struts 102it forms a front mounting surface 118 and a rear mounting surface 116that various EFEM components may mount to (see FIGS. 6-10). In general,the spine 100 creates at least three parallel and co-linear mountingsurfaces: the front face 110 of the upper portion 112, the frontmounting surface 118, and the rear mounting surface 116. As will bedescribed later, the EFEM components mount to one of these threesurfaces. These three surfaces have a known spacial relationship betweenthem, and thus components mounted to these surfaces may be aligned withminimal adjustments, or require no adjustments at all.

The lower support member 106 also creates an air flow area 121 locatedbetween the front mounting surface 118 and the rear mounting surface116. The air flow area 121 is designed to accommodate a FOUP dooropen/close module 139 that has been guided away from the port dooropening and lowered down into the air flow area 121.

Isolating the FOUP door open/close module 139 from the area the waferengine 300 operates within has many advantages. For example, a singleairflow generated by an FFU 150 is divided into two isolated air flows.One air flow will be directed towards the FOUP door open/close module139, while a second separate air stream will be directed into the waferengine area. The two isolated air flows will provide a cleanerenvironment for the FOUP/port door assembly 139 than if a single airflow was circulated for both the wafer engine area and the FOUP dooropen/close module 139. If there was only a single air flow path for boththe wafer engine 300 and the FOUP assembly 130 particles created by thewafer engine, 300 may contaminate the FOUP/pod door assembly 139.

The rear mounting surface 116 of the lower support member 106 alsooperates as a protective barrier between the FOUP door open/close module139 and the wafer engine area. The rear mounting surface 116 preventsparticles generated by the wafer engine 300 from entering the air flowarea 121 storing the FOUP door open/close module 139. The rear mountingsurface 116 also allows the wafer engine 300 to have localized filteringand exhaust systems that exhaust “dirty” air containing particles belowthe wafer plane while not contaminate the FOUP door open/close module139 (described hereinafter).

The spine structure 100 as shown in FIGS. 4-5 is configured as a fourFOUP I/O port EFEM. It is within the spirit and scope of the inventionfor the EFEM to include any number of I/O ports. Additionally, the EFEMmay include spaces or blank I/O ports located between each I/O port thatwafers will be transported through. As previously mentioned, the spinestructure 100 is scalable. The number of vertical struts 102, and thelength of the upper support member 104 and the lower support member 106may be modified to match the I/O port configuration required for theEFEM.

Each vertical strut 102 also has a cam guide 124 machined into the sidesurface. The cam 124 operates as a track or channel for guiding the FOUPdoor open/close module 139 rearward away from the FOUP 10 andsubsequently downward into the air flow area 121. The movement of theport/pod door assembly 139 may be controlled by a motor assembly (notshown) located within the processing station. Such a motor assembly isknown in the art and does not require further disclosure. It is withinthe scope and spirit of the invention to mechanically guide and move theFOUP door 12 and port door 140 into the storage area 121.

The FOUP docking interface shown in FIGS. 6-7 illustrate several EFEMcomponents mounted to the spine structure 100. By way of example only,the components may include a wafer engine or robot 300, a FOUP supportassembly 130, a FOUP docking/isolation plate 138, and a port door 140.The FOUP support assembly 130 includes a FOUP advance support 132, aFOUP advance module 133, and a FOUP support plate 134.

In order to transfer the workpieces from the FOUP 10 into themini-environment (see FIG. 10—“Class-1 Area”) a FOUP 10 is manually orautomatedly loaded onto the port advance plate 134 so that the FOUP doorfaces the load port door 140. A conventional load port door 140 includesa pair of latch keys which are received in a corresponding pair of slotsin the door latching assembly mounted within the FOUP door. An exampleof a door latch within a FOUP door adapted to receive an operate withsuch latch keys is disclosed in U.S. Pat. No. 6,188,323, entitled “WAFERMAPPING SYSTEM,” issued to Rosenquiest et al., which patent is assignedto the owner of the present invention, in which patent is incorporatedby reference herein in its entirety. In addition to decoupling the FOUPdoor from the FOUP shell, rotation of the latch keys also lock the keysinto their respective FOUP door slots. There are typically two latch keyand slot pairs, each of which pairs are structurally and operationallyidentical to each other.

A pod advance plate 134 typically includes three kinematic pins 135, orsome other registration feature, which mate within corresponding slotson the bottom surface of the FOUP 10 to define a fixed and repeatableposition of the bottom surface of the FOUP 10 on the advanced plate 134.Once a FOUP 10 is detected on the pod advanced plate 134, the FOUP 10 isadvanced toward the port door 140 until the FOUP door lies in contactwith or is near the port door 140. It is desirable to bring the frontsurfaces of the respective doors into contact with each other to trapparticulates and to insure a tight fit of the port door latch key in theFOUP door key slot. U.S. patent application Ser. No. 09/115,414,entitled “POD DOOR TO PORT DOOR RETENTION SYSTEM,” by Rosenquist et al.,and U.S. patent application Ser. No. 09/130,254, entitled “POD TO PORTDOOR RETENTION AND EVACUATION SYSTEM,” by Fosnight et al. disclosesystems insuring a tight, clean interface between the FOUP 10 and portdoors. These applications are assigned to the owner of the presentinvention, and are both incorporated by reference herein in theirentirety.

Once the FOUP 10 and port doors are coupled, linear and/or rotationaldrives within the EFEM move the FOUP 10 and port doors together into theinterior of the EFEM, and then away from the load port opening so thatthe workpieces may thereafter be accessible to the wafer engine 300. Asshown in FIG. 10, the port door 140 is affixed to the FOUP door and acontroller actuates a slide to translate the carrier and port doorsalong the cam 124 located in each vertical strut 102. The cam 124 guidesthe interlocked carrier and port doors vertically down into the air flowarea 121 of the lower support member 106. As previously mentioned, theport door 140 and FOUP door are isolated from the rest of the Class-1area while stored in the air flow area 121. The linear slide androtational drive configurations (not shown) are known in the art and donot require further disclosure. A linear slide may be comprised of alinear bearing and a drive mechanism. By way of example only, the linearbearing may include a ball or air bearing. Similarly, the drivemechanism may include a motor with a cam lead screw, a belt drive, or alinear motor. The rotational drive may be comprised of, by way ofexample only, a gear motor, a direct drive, a belt drive, or othersimilar means.

After the FOUP 10 and port doors are moved away from thedocking/isolation plate 138, the wafer engine or robot 300 may transferworkpieces into the tool front end without interference from the storedFOUP 10 and port doors. Once operations on a workpiece lot at the toolhave been completed and the workpieces have been returned to the FOUP10, the controller again actuates the drive and the slide to move thedoors back into the I/O port, where upon the FOUP door is transferredand secured to the FOUP 10.

The docking/isolation plate 138 is mounted to the front face 110 of eachvertical strut 102. The docking/isolation plate 138 isolates theinterior region (Class-1 or “clean” area) of the tool front end from theoutside ambient or exterior region. The docking/isolation plate 138 alsoprovides an interface plane that the FOUP 10 is advanced towards to aclose and controllable proximity (e.g., 0-5 mm separation). The plate138 forms an auxiliary seal with the FOUP 10 and the port door 140. Anauxiliary seal allows a separation to exist between the plate 138 andthe FOUP 10, but still creates an airtight seal between the plate 138and the FOUP 10. An airtight seal between the plate 138 and the FOUP 10is desirable to prevent gas from leaking out of the Class-1 Area or tomaintain the inert environment of the load port interface.

The docking/isolation 138 is preferably manufactured from a single pieceof material that includes one or more FOUP openings machined into it.The docking/isolation plate 138 includes registration holes 144 tolocate it accurately with respect to each vertical strut 102. Thisprovides a machined, precision relationship between all the FOUP 10openings for the EFEM. The docking/isolation plate 138 may also compriseindividual pieces of material that mount to each vertical strut 102using the same reference features. The plate 138 may be fabricated frommaterials such as, but not limited to, plastic, metal, sheet metal, oreven glass.

In a preferred embodiment, the docking/isolation plate 138 is machinedfrom a clear material, such as polycarbonate. Machining thedocking/isolation plate 138 from a clear material provides an addedbenefit of being able to see inside the mini-environment or Class-1 Areawhile the tool is in operation. The current E15 load port/SEMI E63 BoltsInterface does not define this feature. The docking/isolation plate 138does not have any structural features and therefore may be secured toeach vertical strut 100 of the spine 100 by only a few bolts and/orpins. Thus, the docking/isolation plate 138 may be easily removed.Further, since none of the EFEM components align with reference to thedocking/isolation plate 138, the docking/isolation plate 138 may beremoved from the EFEM without disturbing the set up or alignment of theEFEM components such as the port door 140, the FOUP advance plate 134,or the wafer engine 300. This provides a simple method of gaining accessto the “clean” area (Class-1 area in FIG. 10) of the EFEM for service,maintenance, or error recovery.

FIG. 8 illustrates the wafer engine 300 mounted to the spine structure100. From this view, it is clearly shown that the wafer engine 300 maytravel linearly to access all the I/O ports of the EFEM. The waferengine 300 travels along a rail assembly 302, which is mounted to therear mounting surface 116 of the lower support member 106. In thisembodiment, the linear drive 302 is shown as a belt drive. It is withinthe scope and spirit of the invention for the linear drive 302 tocomprise other drive systems such as, but not limited to, a directdrive, a linear motor, a cable drive, or a chain link drive. Thecomponents of the wafer engine 300 will be described later. Such drivesystems are well known in the art and do not require further disclosure.

FIG. 9 illustrates further detail of the rail system 302 shown in FIG. 8mounted to the spine structure 100. The rail system 302 includes anupper x rail 310, a lower x rail 312, and a carriage guide 311, allmounted to the rear mounting plate 118 of the lower channel 106. In apreferred embodiment, the upper x rail 310 and the lower x rail 312 arecircular or tubular, and are substantially parallel to each other.Engaging the upper x-rail 310, the lower x-rail 312, and the carriageguide 311 is an x carriage 304. The upper and lower x rail 310 and 312also serve as the main support for the wafer engine 300.

FIG. 9 also illustrates a control box 147 that is preferably locatedbelow the FOUP advance assembly 130. The EFEM requires many electricalcontrol devices (e.g., control wiring, PCBs, etc.). It would be anadvantage if these devices were easily accessible for maintenance andrepair. The control box 147 provides an area to mount the electricaldevices. In a preferred embodiment, the control box 147 has a pivotingfront cover that may drop down for access to the electrical componentsinside. Within the control box are located many of the electricalcomponents and control systems required to power and operate the EFEMcomponents. It is intended that these electrical components may beeasily accessed for maintenance purposes and therefore the pivotingfront cover of the control box 147 is secured by a few bolts and/or pinsthat may be removed and allow the front cover to pivot downwards towardsthe floor of the fab.

As shown in FIGS. 10, and 30-31, the spine structure 100 architectureprovides a way to minimize the footprint of the EFEM and seal the cleanvolume of the system while still maintaining overall system accuracy.The FFU 150 mounts to and seals with the upper channel 104 and a toolinterface panel 154 to form the top of the EFEM. The front seal isprovided by mounting the docking/isolation plate 138 to the front face110 of each vertical strut 102. A sheet metal panel 152, which ispreferably a perforated surface, mounts to the lower support member 106to form the bottom of the EFEM. The panel 152 also acts as an exhaustplate that allows the exhaust flow from both the FFU 150 and the waferengine 300 to pass out into the ambient environment. Each side of theEFEM is sealed by end plates 156 which mount and seal with the spine 100(see FIG. 30), the tool interface panel 154, the panel 152, and the FFU150. As shown in FIG. 10, the clean air flow from the FFU 150 and theslide body FFU 420 travel through the mini-environment, or Class-1 area,and out through the bottom panel 152 and the lower channel 106. Theairflow exhausted from the Z slot fan 354 (described hereinafter), whichcontains particles generated by the vertical drive 380, also travelsthrough the bottom panel 152. The airflow from the Z slot fan 354 neverenters the clean mini-environment.

In general, the spine 100 creates a single reference system to calibrateand align the EFEM components, such as the wafer engine 300 and the FOUPadvance assembly 130. Each separate EFEM component may calibrate to aknown and fixed position, such as a vertical strut 102 instead ofcalibrating and aligning with respect to each other. This method ofcalibration is greatly simplified over the conventional proceduresrequired today.

Spine Structure with a Backbone

FIGS. 11-13 illustrate another embodiment of a spine structure. Theprimary structural elements of this embodiment include a horizontal beam170, registration struts 172, and a front mounting plate 174. As shownin FIG. 11, the horizontal beam 170 is preferably mounted to the bottomportion of each registration strut 172 to form a rigid frame. The frontmounting plate 174 is also mounted to each registration strut 172,providing a surface for the exterior EFEM components (e.g., FOUP advanceassembly 130) to mount to. The horizontal beam 170 may be manufacturedfrom, by way of example only, an aluminum extrusion, steel tube, astructure made from bent sheet metal, a flat plate, a laminated plate,or most likely a combination of some of the above. The horizontal beam170 also provides a surface for the linear drive 306 (describedhereinafter) to mount to. Similar to the spine structure 100, thisembodiment provides a single reference to mount and align EFEMcomponents.

FIG. 12 illustrates that the FOUP door 12 and the port door 140 arepreferably still stored in an isolated area within the Class-1 Area.Accordingly, the beam 170 must be spaced apart from the registrationstruts 172 far enough to allow the FOUP door 12 and the port door 140 tofit between the beam 170 and the registration strut 172. As shown inFIG. 12, separators 171 are placed between each registration strut 172and the beam 170 to create the storage area. It is within the scope andspirit of the invention to create the storage area through other means.The beam 170 also functions as a protective barrier, preventingparticles created by the wafer engine 300 from contaminating the FOUPdoor 12 or the port door 140.

FIG. 13 illustrates that the support structure or spine may include thebeam 170 having a CNC milled aluminum plate 176 mounted to the beam 170for supporting the x-axis rails 310 and 312. This structure is furtherrigidified by a sheet metal U-shaped section 175. The verticalregistration struts 172, which are mounted to the section 175, arealigned similarly to the vertical struts 102 in the previous embodiment.As shown in FIG. 11, a front mounting plate 172 mounts to theregistration struts 174. EFEM components, such as the FOUP advanceassembly 130, mount to the front mounting plate 172.

The beam 170 may be positioned between the wafer engine 300 and the podopeners below the work space of the wafer handler. The beam 170, howeverit is constructed, provides one structural common element that the EFEMcomponents precisely mount to, eliminating the need for time consumingadjustments in the field when an EFEM is installed or replaced.

Single Frame/Shell

FIGS. 14-16 illustrate yet another embodiment of the spine structureconfigured as a FOUP docking station. In this embodiment, the spinestructure that the EFEM components mount to is a single frame or shell202. The frame 202 serves as a single reference for the interior, (e.g.,engine wafer 300) and exterior components to mount to and align with(e.g., FOUP advance assembly 130) components similar to the spinestructure 100.

As shown in FIG. 14, the spine structure 200 includes three load portassemblies 204 mounted to the frame 202. Each load port assembly 204 issimilar to the load port assembly 130 disclosed in the preferredembodiment. A load port door 206, which isolates the Class-1 area fromoutside ambient conditions, corresponds to each load port assembly 204for engaging and removing the FOUP door from the FOUP shell. It iswithin the scope and spirit of the invention for the frame 202 to havemore of fewer I/O ports. Similarly, the frame 202 may include afilled-in or solid I/O port located between I/O ports where wafers aretransferred through.

The frame 202 is preferably formed from a single piece of material. Byway of example only, the frame 202 may be created by a punch press. Theframe 202 may be manufactured from many different materials. By way ofexample only, the frame 202 may be manufactured from material such as,but not limited to, sheet metal, polypropylene, composites, or plastics.The frame 202 may also include an anodized surface finish to prevent orreduce outgassing. Whether the frame 202 is manufactured from a singlepiece of material or separate parts, the frame 202 is scalable.Accordingly, the frame 202 may be customized to create as many FOUP I/Oports as necessary for the EFEM.

FIG. 15 illustrates several of the EFEM components mounted to the frame202. The preferred embodiment of the frame 202, which is manufacturedfrom a single piece of stainless steel, is flexible. By way of exampleonly, the frame 202 may also be manufactured from an aluminum sheet. TheEFEM must be rigid enough to provide accurate support and alignmentpoints for the EFEM components. Additional supports 210 are mounted tothe frame 202 to provide rigid and accurate support points forcomponents such as the linear drive 254, filter unit 220, FOUP advanceassembly 208, and tool interface plane.

To promote air flow through the load port interface, the top surface 201and the bottom surface 203 of the frame 202 are perforated. A fan/filterunit 220 may be mounted to, and form a seal with, the top surface 201 ofthe frame 202 to control the rate and quality of the air through theframe 202. Such fan/filter unit technology is well known in the art anddoes not require further disclosure. A single fan/filter unit 220 may beappropriate to achieve the air flow rate desired. However, as the frame202 increases in size and thus volume, the frame 202 may requiremultiple fans to maintain the desired environmental conditions. If theinterior of the EFEM is not isolated from outside atmospheric conditions(not an inert environment), air may be drawn into the cleanmini-environment by the FFU 220 and vented out through the perforatedholes 212 in the bottom surface 203 of the frame 202.

If the EFEM is an inert system, a flow capture chamber 224 may bemounted to and sealed with the bottom surface 203 of the frame 202 sothat the air flow created by the fan/filter unit 220 is completelycontained and re-circulated. The end cap 210 may also have a flow returnpath guiding the air exiting the flow capture plenum 224 back to thefan/filter unit 220 for re-circulation.

Due to the minimal enclosed volume created by the frame 202 the presentinvention is a very efficient system from an air handling standpoint. Amini-environment with a smaller volume of air to control and filtermakes it easier to maintain the cleanliness of the air. Inert systems,or systems requiring molecular filters which degrade as more air pushthrough them, also benefit from a mini-environment containing a smallervolume of gas. By way of example only, filters will require changingless frequently if a smaller volume and rate of gas is passed throughthem.

System Volumetric Space Utilization

One of the key differentiators of all of the EFEMs previously described(e.g., spine structure, backbone, and frame) is the fundamental changein space utilization. The space utilization feature will only bereferenced to the spine structure 100 even though this concept appliesto al the embodiments disclosed in this application. In conventionaltool front ends, the front end occupies all space from the front of theload port (load face plane) to the process tool face, and from the floorof the fab up to its highest point, typically the top of the FFU and thefull width of the front end.

An EFEM constructed from the spine structure 100 creates significantspace below the load ports 130, and the clean wafer engine area may begiven back to the process/metrology tool or used for other purposes.Additionally, the overall depth of the enclosed area or mini-environmentis also decreased from what conventional EFEM configurations require.The front of the wafer engine radial slide body 400 may be rotated intothe typically unused area for the FOUP door mechanism resides betweenthe vertical struts 102. The space may be given back to the process toolas well as the end user who may realize lower foot print requirementsfor the overall tool. The configuration of the wafer engine 300 takesadvantage of these new and smaller space constraints. For example, theradial slide 400 may reach further into the process tool than anon-offset version.

As a result of the much smaller envelope of the system it isconsiderably lighter, and if mounted on the independent rolling frame,may be rolled away from the process tool to provide direct access to thetool. Since the system is also shorter than typical process tools, thespace above it may be used for other purposes as well, such as localFOUP 10 buffering for the AMHS system. With conventional overhead hoistAMHS systems, local buffer stations may only be placed between loadports or tools since they require unobstructed overhead path to the loadport. With the slide out shelf arrangement, the material could be storedin an otherwise unutilized area directly above the enclosed area of theintegrated EFEM.

As shown in FIGS. 30-31, the system may be integrated with the processtool in several ways. It is designed to require support at four points.Two points in the front at the base of the two outer vertical strutsprovide attached and leveling points. Two points at the rear lowercorner of each end plate provide the rear support locations. The supportpoints could be provided by a roll out frame which would provide an easyway to move the system away from the process tool. It could be supportedby frame members from the process tool which could be cantilevered outfrom the tool or supported from the floor. It might also be acombination of the two where the roll out frame could be used to liftthe system off kinematic points provided by the process tool frame.

Any of the integrated mini-environments and structures 100 or 200 aspreviously described mount to the front of a tool associated with asemiconductor process. As used here, such tools include, but are notlimited to, process tools for forming integrated circuit patterns onsemiconductor wafers, metrology tools for testing various properties andwork pieces, and stockers for large scale storage of work piececarriers. As used herein, a tool may be simply an enclosure so that thework piece handling on the back side of the plate as describedhereinafter may be carried in an enclosed space. By way of example only,the structure 100 according to the present invention may comprise asorter for arranging and transferring work pieces with one or morecarriers.

Alternatively, the structures 100 may comprise a sorter or a stand-aloneprealigner. In both the sorter and stand alone prealigner embodiments,the work piece operations are carried out entirely by the EFEMcomponents mounted to the structure 100. The enclosure that forms theClass-1 Area is also based from the structure 100 provides an enclosed,clean environment in which the work pieces may be handled. In severalembodiments of the present invention, the structure 100 may beconsidered as being part of the tool (see FIG. 3A). In other embodimentsof the present invention, the system may be affixed to but consideredseparate from the tool (FIGS. 29A-29D).

As best shown in FIG. 10, the FOUP docking station is formed around thespine 100. A bottom pan 118 is secured to, and forms a seal with, thebottom support member 106. In a preferred embodiment, the bottom pan 118is perforated surface to allow air from the FFU 150 to pass through. TheFFU 150 is secured to, and forms a seal with, the upper support member104. A wafer transfer plate 122 is secured to, and forms seal with, thebottom pan 118 and the FFU 150. The wafer transfer plate 122 may includetransfer windows 121 that allow the wafer engine 300 to transfer wafersbetween the Class-1 Area and the process tool.

The system forms an air tight seal to maintain the Class-1 environment.An air tight seal is created between both the spine 100 and the bottompan 118, the spine 100 with the FFU 150, and the wafer transfer plate122 with both the FFU 150 and the bottom pan 118. Generally, thepressure within the Class-1 Area is maintained at a level higher thanthat of the atmosphere surrounding the Class-1 Area. This pressuredifferential prevents unfiltered air from entering the Class-1 Area.Accordingly, airborne particles or contaminates are blown out of theClass-1 Area through the openings in the bottom pan 118. On occasiontools operate in a hostile environment, such as for example, a purenitrogen environment. In such an environment it is necessary tocompletely isolate the Class-1A Area from the outside surroundingenvironment. A plenum may be secured to, and sealed with, the bottom pan118, so that the mini-environment within the structure 100 is completelyisolated from atmospheric conditions. A plenum 224 (see FIG. 14) may bemounted to the bottom pan 118 to capture the air and recirculate it backtowards the fan/filter unit 150 mounted to the spine 100.

Wafer Engine

In general, the wafer engine 300 illustrated in FIGS. 18-23 minimizesmechanical inertias with respect to frequency of use and criticality ofwafer transfer cycle time. By way of example only, some of the benefitsresulting from this wafer engine 300 include (1) achieving faster waferswap times, (2) a lower total system weight, and (3) a more compact,unified package. The wafer engine 300 may operate within any of theembodiments of the unified spine 100 disclosed in this application, oroperate as a stand-alone device.

A preferred embodiment of the wafer engine 300 is illustrated in FIGS.18-19. The wafer engine 300 includes four main coordinated drives tooptimize the transfer of wafers within the EFEM. The four drives move awafer along an x-axis, a theta axis, a z-axis, and a radial or r axis.

The wafer engine 300 has a linear drive assembly 302 that moves thewafer engine 300 along an x-axis. Movement along the x-axis allows thewafer engine 300 to access each FOUP I/O port. The linear drive assembly302 includes an x-carriage 304 and a rail system 306. The x-carriage 304slidably engages the upper x-rail 310 and lower x-rail 312. The railsystem 306 is mounted to the rear mounting plate 116, and includes anupper x-rail 310 and lower x-rail 312. The upper x-rail 310 and lowerx-rail 312 extend along the x-axis and are substantially parallel toeach other. The break lines running through the rail assembly 306 inFIG. 18 shows that the rail assembly 306 may be of any length. The railassembly 306 is scalable so that the wafer engine 300 may travel alongthe rail assembly 306 to access, for example, the wafers stored in eachFOUP 10. The rotational drive 350 of the wafer engine 300 is alsomounted to the x-carriage 304. Thus, movement by the x-carriage 304drives the wafer engine 300 along the x axis.

The wafer engine 300 may also rotate, pivoting about a theta (θ) axis.In a preferred embodiment, and as shown in FIG. 18, the rotational drive350 includes a support column 364 that extends along the theta axis andmounts to a z-axis support 370. The rotational drive 350 includes atheta motor 362 to drive and rotate the support column 364. Therotational drive 350 may rotate in either a clockwise orcounterclockwise direction. The rotational drive 350 may also mountdirectly to the vertical drive 380. Preferably, the theta axis does nottravel through the center of the slide body 400. The advantages of thisoff-center configuration of the slide body 400 will be discussed later.

The rotational drive 350 further includes a fan extension platform 352.In a preferred embodiment of the wafer engine 300, and as shown in FIG.20, a z slot fan 354 is mounted to the underside of the fan platform352. This configuration of the wafer engine 300 locates the z slot fan354 near the theta motor 362 and provides and air vent to exhaust theair driven through the z column 380 of the wafer engine 300. The airflushed through the z column 380 is projected downward, away from anywafer that is being transported by the wafer engine 300 (see FIG. 21).Alternatively, the airflow may be exhausted through, and out the bottomof, the rotational drive 350.

The vertical drive column 380 is mounted to the support member 370 andextends upward along the z-axis. The drive column 380 moves the slidebody 400 (described hereinafter) of the wafer engine 300, and thus thewafer, up and down along the z-axis. In one embodiment, and as shown inFIG. 19, the drive column 380 is an elongated column that extendssubstantially perpendicular from the support member 370. A driveassembly is located within the drive column 380 and includes a z-drivemotor 382, a z cable way 384, a z guide rail 386, and a z ball screw388. Such drive means are well known in the art and do not requirefurther disclosure. It is within the scope and spirit of the inventionto move the slide body mechanism 400 by other means.

The slide body 400 preferably includes an upper end effector 402 and alower end effector 404 for quickly swapping individual wafers along ther-axis. The slide body 400 supports the upper and lower end effectors402 and 404 such that they are parallel to the wafers stored in eachFOUP 10. As shown in FIG. 19, the upper end effector 402 and lower endeffector 404 travel along a similar rectilinear path. The upper endeffector 402 and lower end effector 404 are separated by a distancesufficient to allow the lower end effector 404 and the upper endeffector 402 to simultaneously store wafers. The slide body 400 includesradial drive motors 410 for moving the upper end effector 402 and lowerend effector 404 linearly along the radial or r-axis.

The upper end effector 402 is supported by an first support 406 and thelower end effector 404 is supported by a second support 408. The upperend effector support 406 and lower end effector support 408 eachslidably engage and travel within a radial guide rail 410 that extendssubstantially across the length of the slide body 400. Each radial drivemotor 410 drives a radial drive belt 414. The radial drive belt 414 a isconnected to the first support 406, and the second radial drive belt 414b is connected to the second support 408. The radial drive motor 410 mayrotate in a clockwise or counter-clockwise direction to rotate theradial drive belt around a radial drive pulley 416 and an end idlerpulley 418 and to extend and retract the respective end effector. Such adrive mechanism is well known in the art and does not require furtherdisclosure. It is within the scope and spirit of the present inventionto have other means to move a wafer along the radial or r-axis.

The wafer engine 300 has many moving parts. Moving parts tend to createparticles. For example, the continual extension and retraction of theupper end effector 402 and lower end effector 404 will createparticulates within the mini-environment. To prevent the particulatesfrom contaminating the wafer located on either end effector, a slidebody fan/filter unit (FFU) 420 is mounted to the underside of the slidebody 400. The slide body FFU 420 continuously pulls air in through theslide body slide slots 420, pulls the air through the slide body 400,filters the air, and then exhausts the air out into the Class-1 Area.This localized filtering of the air flow greatly reduces the amount ofparticles placed into the Class-1 Area.

Conventionally, most mini-environments include a single fan/filter unitthat circulates the air through the mini-environment and only filtersthe air flow as it flows into the EFEM. Any particulates created withinthe mini-environment downstream of the fan/filter unit remain in theclean area until they are exhausted out of the EFEM. It is desirable tominimize the number of particulates within the mini-environmentespecially since the trend in semiconductor manufacturing more and morerequires a lower tolerance of particle contamination on the wafers.

The localized filtering of the wafer engine 300 removes particlescreated by any rotating or sliding mechanism located on the wafer engine300 as the particle is created. In a preferred embodiment, and as shownin FIGS. 19 and 21, a local fan/filter unit or fan system is locatedapproximate to both linear drives of the z column 380 and slide bodymechanism 400. As specifically shown in FIG. 21, the fan/filter unitmounted to the slide body mechanism 400 exhausts filtered air into theclean mini-environment, while the z slot fan system of the verticaldrive 380 exhausts unfiltered air through the bottom plate of the EFEM.The wafer engine 300 filters and exhausts air into the Class-1 Area ofthe EFEM. If the wafer engine 300 did not have the fan/filter mounted tothe slide body mechanism 400, particles created by the slide bodymechanism 400 would travel through the Class-1 Area and contaminate thewafer supported by either end effector.

FIG. 20 illustrates another embodiment of the wafer engine 300. In thisembodiment, the slide body 400 engages the z column 380 such that the zcolumn 380 is substantially along the r axis. Similar to previousembodiments of the wafer engine 300, this embodiment includes a thetamotor 362, a vertical drive column 380 and a radial slide body 400. Thetheta motor rotates the wafer engine about the theta axis, the z columnmoves the radial slide body 400 linearly along the z axis, and theradial slide body 400 moves the end effector 401 along the radial orr-axis. Accordingly, the wafer engine and thus the wafer will rotateabout the theta axis any time the theta motor 362 rotates. Thisembodiment may also include a fan/filter unit mounted to the radialslide body 400 in a v slot fan similar to the previous embodiment of thewafer engine 300.

As previously mentioned, the slide body 400 of the wafer engine 300 mayinclude different configurations of end effectors. As illustrated inFIGS. 18-19, the upper and lower end effector 402 and 404 may include apassive edge support. Such a configuration is known in the industry aspassive edge grip end effectors for 300 mm wafers. FIG. 22 illustratesthat the upper end effector 402 may include an active edge grip, whilethe lower end effector 404 may include a passive edge support.Alternatively, the end effectors 402 and 404 may include any combinationof, for example, a vacuum grip with backside contact, a reduced contactarea, removable pads.

Similarly, the radial drive 400 may include different types of endeffector for handling wafers at different stages. For example, one endeffector may handle only “dirty” wafers, while the second end effectormay handle only “clean” wafers. Alternatively, one end effector may bedesignated to align and read the wafer ID before transferred to theprocess tool, while the second end effector may include high temperaturepads for handling hot wafers after being processed.

Integrated Tools in Wafer Engine

A conventional wafer handling robot transports individual wafers, forexample, from a FOUP 10 to a separate processing station. The processingstation inspects or aligns the wafer and then the wafer handling robotmay transport the wafer to the next station. Often the wafer handlingrobot must sit idle or return to a FOUP 10 to transport a second waferwhile the process station operates. Such an operation reduces thethroughput of the system.

In one embodiment, the wafer engine 300 includes a slide body 400 thatmay perform one or several of these functions normally performed at aseparate processing station. Integrating one or several of thesefunctions into the slide body 400 will increase the throughput of thesystem and reduce the footprint of the EFEM.

FIGS. 22-23 illustrate a wafer engine 300 equipped with a wheeledaligner 440 and ID reader 430 mounted on the slide body 400. Thisembodiment is similar to the wafer engine 300 as shown in FIGS. 18-19,with the addition of a wheeled aligner 440 mounted on the upper endeffector 402, and an ID reader 430 mounted to the slide body 400. It iswithin the spirit and scope of the invention for the lower end effector404 to include a wheeled aligner.

The ID reader 430 may view up or down for reading marks on top and/orthe bottom surfaces of the top or bottom of the wafer. It is within thescope and spirit of the invention for the ID reader 430 to be mounted tothe vertical drive 380, or be mounted in a fixed location elsewhere onthe wafer engine 300. IN the preferred embodiment, it is advantageous tomount a top side ID reader 430 on the slide body 400 for fast IDreading. A second ID reader may be mounted at a fixed location elsewherein the EFEM for reading the bottom side T7 mark for confirmation orclarification of wafer ID if required.

If ID reading is required but wafer orientation is not important, thealigner may be eliminated and the ID reader 430 may view the ID mark inwhatever location the wafer arrives on the end effector. To facilitatethis operation, the ID reader 430, or a mirror assembly, may be rotatedabove the surface of the awfer to view the ID mark. This eliminates theneed to rotate the wafer for ID reading and thus improves cleanlinessand throughput.

An aligner controls the rotation of the wafer about an axis,, such as bywheel or other means. FIGS. 23-24 illustrate one embodiment of an endeffector with a wheeled aligner 440. The wheeled aligner 440 includes adrive system 449 and a paddle plate 442. The paddle plate 442 is themain support for the wafer. Located at the end of the paddle plate 442are two sets of passive tip wheels 446 and two pads 448. The wheels 446and pads 448 support the wafer at different times during alignment. Adrive wheel 450, located at the back end of the paddle plate 442,supports the wafer along a third contact surface while the wafer isbeing aligned.

In one embodiment, wheeled end effector 440 slides underneath a waferlocated in a FOUP 10 and is raised until the wafer is supported by thepads 448. The pads 448 preferably only support the wafer along itsbottom edge. To align the wafer, the wafer is pushed forward by thedrive wheel 450 and up onto the wheels 446. The wafer is lifted off thepads 448 and is fully supported by the drive wheel 450 and the tipwheels 446. At this point the drive wheel 450 may rotate to spin thewafer in situ. This operation may be performed while the wafer engine300 is transporting the wafer. The wafer engine 300 does not have toremain in place to align the wafer.

Alternatively, as shown in FIG. 26B, the slide body 400 may include avacuum chuck aligner 411. The drive mechanism for the vacuum chuckaligner 411, including a lift and rotation axis, may reside inside theslide body 400. A sensor 409 may be mounted to the end effector 403 tolocates the edge of the wafer while it remains on the end effector. Thesensor 409 may also be mounted to an structure that is independent ofthe end effector 403. In general, the sensor 409 may be located atvarious locations as long as the sensor 409 can be positioned to readthe top surface of the wafer.

The edge position may be mapped relative to the rotation angle to findthe center and orientation of the wafer. The sensor 409 functions as asecondary feedback device. The location of the sensor 409 is knownrelative to the wafer at all times. Thus, the sensor 409 may send errorsignals indicating that the wafer is not aligned. Since the alignerreceives additional error data from the sensor 409, an aligner with sucha sensor will improve the accuracy of the aligner. The wafer can then bereoriented by the chuck 411 and placed on center at the next drop offstation by the wafer engine 300.

The sensor 409 may be mounted independently within the EFEM and be aseparate component from the wafer engine 300. In such a configuration,the wafer is placed on the chuck 411 that can rotate. The sensor 409,mounted on a mechanism that has position control and measuring means(not shown), is moved to the proximity of the wafer edge until thesensor signal is at a desired level. The wafer can then be rotated whilethe sensor mechanism uses the signal from the sensor 409 to keep theposition of the sensor 409 at the this desired level, effectivelykeeping the sensor 409 at the same relative position to the wafer edge.As the wafer is rotated, the sensor position is recorded with respect tothe angular position of the wafer. This data represents the change inradial position of the wafer edge with respect to wafer rotationalposition, and can be used to calculate the center of the wafer withrespect to the center of the wafer chuck and the orientation of thefiducial. If the sensor signal magnitude is also recorded along with thesensor mechanism position, it can provide additional edge positioninformation that could improve the accuracy of the wafer centercalculations or fiducial orientation.

The wheeled end effector aligner 440 may include other components suchas, but not limited to, an optical notch sensor 452 to detect the notchalong the edge of the wafer. For example, once the notch has beenlocated along the edge of the wafer by the optical notch sensor 452 thedrive wheel 450 may rotate the wafer to the desired position and retractback, allowing the wafer to fall back down onto the pads 448. Thisoperation may be performed while the end effector is in place or ismoving. The ability to align the wafer while it is being transferredbetween FOUPs 10, or between a FOUP 10 and a processing tool, greatlyreduces or eliminates the amount of time that an end effector must sitidle. Further, there is no need for a separate processing station if thewafer engine 300 can align a wafer “on-the-fly.”

The slide body 400 enables a stable mounting platform for a variety ofauxiliary functions, measurements, and sensors to acquire various waferdata. By way of example only, components may be integrated into ormounted to the slide body 400 to detect a wafer edge, detect the notchlocation on the wafer, read the OCR/bar code, perform particulatecounting (back side or front side), determine film thickness/uniformityor circuit element line width, and detect resistivity (via contactprobes or non-contact means) and wafer thickness. Other processes knownin the art for inspecting and marking a wafer may be incorporated intothe slide body 400.

In order to transfer workpieces from a carrier, the end effectors 402and 404 move horizontally under the workpiece to be transferred and thenmoved upward to lift the workpiece off its resting place. The endeffectors 402 and 404 may also include edge grips for supporting theworkpiece at its edges. Alternatively, the end effectors 402 and 404 maybe a blade type end effector for supporting a workpiece by its bottomsurface. In such embodiments, a vacuum source (not shown) may be affixedto or remote from the paddle plate 442, which creates a negativepressure that is communicated through the workpiece handling robot viaflexible vacuum tubes to the surface of the end effector blade. Uponactivation of the vacuum source a negative pressure is formed at thesurface of the end effector blade, creating a suction capable of holdinga workpiece firmly thereon. A vacuum sensor (not shown) of knownconstruction may also be provided on the robot and associated with thevacuum system for detecting when a workpiece is engaged with the endeffector and restricting the pull of air through the vacuum tubes. It isunderstood that the present invention is not limited to the end effectordescribed above and that a variety of end effector designs may be usedas long as the end effector has the capability to pick up and drop offworkpieces.

The slide body 400 may also be adapted to process a wafer andenvironmentally isolate the wafer from the Class-1 Area. By way ofexample only, the slide body 400 may include process tools to eitherheat or cool the surface of the wafer, or conduct thermal surfaceprocessing. In another embodiment, the slide body 400 may include ahousing (not shown) that a wafer may be retracted into and temporarilystored within while the wafer engine 300 is transferring the wafer outof the process tool and within the Class-1 Area. The housing provides aninert or clean environment that has a better than Class-1 Areaenvironment. Such a system may include floating oxygen or an inert gasover the surface of the wafer while it is being transported.

Dual Swap Capability

The time between when a processed wafer is removed from the processstation and when a new wafer is placed into the process station is knownas the “swap time.” For most process tools, the throughput is determinedby the process time plus the swap time. Reducing either increasesthroughput. The process time is the purview of the tool manufacturer,the swap time is the purview of the capital EFEM manufacturer.

For a conventional single end effector wafer handling robot in an EFEM(see FIG. 17), the swap time may be 8 to 16 seconds, depending on thestation arrangement and the speed of the wafer handling robot. Thefollowing sequence of operations are commonly used by such a robot toswap a wafer at a process station. The items contributing to the swaptime are in italics. Items outside of the critical path determiningthroughput are in (parenthesis).

-   -   1. Get wafer from process station    -   2. Put processed wafer to load port    -   3. Get aligned wafer from aligner    -   4. Put aligner wafer to process station    -   [Begin processing wafer]    -   5. (While processing, robot get new wafer from load port)    -   6. (While processing, robot put new wafer to aligner)    -   7. (While processing, aligner align wafer)    -   [Repeat]

A rapid swap robot (e.g. wafer engine 300) has two end effectors andtherefore can dramatically reduce swap time by performing the samefunction as above using the following abbreviated sequence:

-   -   [Process Complete]    -   1. Get wafer from process station with paddle 1    -   2. Put aligned wafer to process station with paddle 2    -   [Process wafer]    -   3. (While processing, get new wafer from load port)    -   4. (While processing, put new wafer to aligner)    -   5. (While processing, aligner align wafer)    -   6. (While processing, get aligned wafer from aligner)    -   [Repeat]

In this case, the swap time may be reduced by 3 to 6 seconds dependingon the speed of the robot. The overall time for the robot to completeall of its motions may be slightly reduced as well. The overall motiontime is of primary importance in applications where the process time isvery low and therefore the items in parenthesis above would enter intothe critical path or throughput.

A further improvement on throughput and reduction in total robot motionscan be made if the robot has align-on-the-fly capability as well asrapid swap capability like the wafer engine 300 having a wheeled endeffector aligner 440. Align-on-the-fly does not reduce swap time, but itdoes reduce overall robot motion time and therefore increases throughputwhere the process time is low, or where the robot must support multipleprocess stations. Also, by reducing the number of robot motions andwafer handoffs, align-on-the-fly can increase robot life and improvecleanliness.

For the align-on-the-fly rapid swap wafer engine, the comparablesequence of operations is:

-   -   [Process Complete]    -   1. Get wafer from process station with paddle 1    -   2. Put aligned wafer to process station with paddle 2    -   [Process Wafer]    -   3. (While processing, get new wafer from load port)    -   4. (While processing, align wafer and simultaneously move to        position for next rapid swap)    -   [Repeat]

Unlimited Z-axis Motion

FIG. 25 illustrates a wafer engine 300′ including an off-center slidebody 400 having a wheeled aligner 454 and ID reader 430, and an extendedz-axis drive column 380′. This embodiment of the wafer engine includesan extended z column 380′ to, for example, to access a stocker, or aload port or process station that may be located above the FOUP I/Oport. Basically, the height of the z-axis drive column 380 or 380′ isunlimited. The wafer engine 300 or 300′ may access a wafer locatedwithin a FOUP 10 by moving the upper end effector 402 or the lower endeffector 404 along the radial or r-axis. The distance that the upper endeffector 402 or lower end effector 404 must travel into the FOUP 10 isdesigned to be a short distance since this is the most often requiredmotion of the wafer engine 300 or 300′. The height of the vertical drivecolumn 380 or 380′ does not effect the distance that either the upperend effector 402 or lower end effector 404 must travel. Thus, the heightof the vertical drive column 380 or 380′ does not effect the motionalong the radial or r-axis.

Conventional wafer handling robots must move the z drive column linearlytowards the FOUP 10 so that the end effector may access and remove thewafer from the FOUP 10. Accordingly, a tall vertical drive column forsuch a wafer handling robot requires moving a large vertical column by amotor or a belt drive. Moving such inertia places great strain on thewafer handling robot. The wafer engines disclosed in this applicationare an improvement over such wafer handling robots because the axis ofmotion, along the radial or r-axis, which is the most commonly traveledare also the shortest distances.

FIG. 27A illustrates that a conventional linear slide robot may reachinto the processing tool 250 mm for transferring and retrieving wafersinto the process tool. Similarly, a convention wafer handling robotrequires a minimum clearance within the EFEM work space of 520 mm sothat the wafer handling robot can maneuver within the EFEM. FIG. 27Billustrates the reach and swing clearance advantage of the off-centerslide body rotation about the theta axis. In a preferred embodiment, theoff-center slide body axis of rotation, shown as the theta axis in FIG.19, is offset by approximately 50 mm. The off-center axis of rotationfor the wafer engine 300 has two distinct advantages. First, the maximumreach of an end effector (e.g., upper end effector 402 or lower endeffector 404) into the processing tool is increased to 350 mm. Second,the minimum clearance required within the EFEM work space is reduced to420 mm. The maximum reach and minimum clearance distances are by way ofexample only. Increasing the reach of the end effector into the processtool, while decreasing the minimum clearance required for the waferengine 300 to maneuver within the EFEM reduces the overall footprint ofthe EFEM.

FIG. 28 illustrates an example motion sequence of the wafer engine 300having a rapid swap slide body 400 with off-center rotation axis. By wayof example only, step one illustrates the wafer engine 300 lifting thewafer at load port area one. Step two illustrates the wafer engine 300retracting the wafer from within load port one along a radial axis. Stepthree illustrates the wafer engine 300 rotating about the theta axis andsimultaneously moving back along the x-axis to avoid collision with loadport one. Step four illustrates the wafer engine 300 moving along thex-axis towards the I/O port of the processing station. Step fiveillustrates the wafer engine 300 continuing to rotate about the thetaaxis and along the x-axis to position the wafer for entry into theprocessing station. Step six illustrates the wafer engine 300 waitingfor the process to complete. Step seven illustrates the wafer engine 300swapping the processed wafer for the new wafer ready to enter theprocessing station. Finally, step eight illustrates the wafer engine 300retracting the processed wafer in a radial axis while simultaneouslymoving along the x and theta axis to return the processed wafer intoload port one, two or three.

The wafer engine 300 and 300′ described above provides several benefitsover conventional wafer handling robots. For most wafer handlingapplications, radial motion needed to insert and remove wafers into andout of a FOUP 10 or a process station has the highest duty cycle andlongest overall distance traveled. The wafer engine 300 places theradial drive 400 as close to the wafer as possible before attempting toaccess the wafer. This placement reduces the moving mass and motion timeof the upper end effector 402 and lower end effector 404, and wear.

The z-drive column 380 occupies the same volume of space that is sweptout by the wafer as the wafer engine 300 rotates. The drive column 380also does not extend below the work plane. A conventional wafer handlingrobot must utilize the area located below the wafer plane to access someof the wafers within the FOUP 10. Typically, the end effector is mountedto the top of a column that travels up and down along the z axis. Thecolumn takes up space that could otherwise be used for other purposes.Similarly, when the column moves horizontally along the x axis, the arealocated below the wafer plane must substantially empty so that thecolumn does not run into and damage any obstacles.

There are several variations and/or modifications that can be made tothe wafer engine 300 that still have the unique elements and benefitspreviously listed above. By way of example only, the x-axis drive 302may be eliminated for some applications. Similarly, a single radial axismay suffice. Further, for some applications (e.g., sorters) may notrequire a rotational drive. Instead, the z-axis drive 380 would mount tothe x-carriage 308. A sorter application, for example, may have all ofthe load ports mounted facing the same direction, and if the alignmentand ID reading is integrated into the wafer engine 300, the need torotate would be eliminated.

FIGS. 29-31 illustrate several configurations of the integrated system.FIG. 29A illustrates the integrated system mounted on a roll out frame.As previously mentioned, conventional EFEMs extend all the way down tothe floor of the wafer fab. With the space savings derived fromconstructing an EFEM from a spine structure 100 or other embodimentsdisclosed in this application, the footprint of the integrated system isgreatly reduced. As shown in FIG. 29A, the integrated system is mountedon a roll out frame so that the load port assemblies remain at the SEMIstandard height of 900 mm. When this integrated system is bolted to thefront end of a processing tool, and in a preferred embodiment, therewill be approximately 2 feet of open space located beneath theintegrated system and the wafer fab floor. This space has never beenavailable in a wafer fab before. Such a space will allow semiconductormanufactures to place other items such as an electrical control boxunderneath the integrated system.

Alternatively, a processing tool may now have a maintenance access thatcan be reached by crawling underneath the integrated system. The rollout frame also improves the overall maintenance features of theprocessing tool that the integrated system is bolted to. By way ofexample only, if maintenance needs to be performed on the processingtool, the integrated system may be unbolted from the processing tool,the wheels of the roll out frame may be unlocked, and the integratedsystem may be rolled away from the front end of the processing tool. Aconventional EFEM that is bolted to the processing tool does not containwheels that the EFEM can be rolled out on, and is typically such a heavydevice that it requires more than one maintenance person to lift theEFEM away from the process tool. As previously mentioned, the integratedsystem of the present invention weighs only several hundred pounds andthus can be easily rolled away from the front of the processing tool bya single maintenance person.

FIGS. 30 illustrates the integrated system integrated into a processtool. By way of example only, the system of the present invention may beintegrally formed and mounted to a process tool. One advantage of thissystem is that if every process tool within the wafer fab had anintegrated system mounted to it, the wafer fab would have a front andload system that can be configured to the needs of each process tool yetcontain a similar environment to reduce the need for stocking spareparts and training maintenance personnel.

Electrical Control System

Conventional EFEMs must contain a power distribution that is compatiblewith the power requirements for countries across the world. Therefore,most EFEMs today must be able to adapt to either a 110V or a 220Vsystem. Being able to a adapt to either power system requires that anEFEM include power components such as step down or step up transformersas well as other electrical components. Such electrical components mustbe mounted within the EFEM and thus increase the footprint of the EFEM.

The EFEM of the present invention is designed for all electricalcomponents such as the FOUP advance plate assembly, the wafer engine 300and the fan/filter unit 150 to operate all under a 48V system. Ingeneral, the EFEM of the present invention may be electrically connectedto either a 110V or 220V system that will stepped-down to 48V to controlall of the elements described previously. Simplifying the electricaldistribution system of the EFEM eliminates the need for many of theconventional power distribution components such as the step uptransformer and thus further decreases the footprint of the EFEM of thepresent invention.

1-12. (canceled)
 13. In a workpiece handling tool for accessingworkpieces stored in a container, the workpiece handling tool includinga container support structure, a port door and a workpiece handlingrobot, a frame comprising: a first elongated structural member and asecond elongated structural member, said first and second elongatedstructural members each having a first end, a second end, a front face,and a rear face; a lower support secured to said second end of saidfirst and second elongated structural members, said lower supportincluding a front component partially covering said front face of saidfirst and second elongated structural members and a rear componentpartially covering said rear face of said first and second elongatedstructural members; and a port door storage area for temporarily storingthe port door, said port door storage area located between said frontcomponent and said rear component of said lower support.
 14. The frameas recited in claim 13, further including an upper support secured tosaid first end of said first and second elongated structural members.15. The frame as recited in claim 14, wherein said upper supportcomprises sheet metal.
 16. The frame as recited in claim 13, whereinsaid lower support comprises a single piece of material.
 17. The frameas recited in claim 13, wherein said lower support comprises multiplepieces of material.
 18. The frame as recited in claim 16, wherein saidlower support comprises sheet metal.
 19. The frame as recited in claim14, wherein said upper support and said lower support, when secured tosaid first and second elongated structural members, maintain said firstand second elongated structural members substantially parallel to eachother.
 20. The frame as recited in claim 13, wherein the frame providesan input/output port for a workpiece to pass through, said input/outputport located at an elevation between said first and second end of saidfirst and second elongated structural members.
 21. The frame as recitedin claim 13, wherein said front component of said lower support providesa barrier between a port door stored in said port door storage area andan ambient atmosphere external to the workpiece handling tool.
 22. Theframe as recited in claim 13, wherein said rear component of said lowersupport provides a barrier between a port door stored in said port doorstorage area and the workpiece handling robot.
 23. The frame as recitedin claim 13, further including a port door drive mechanism for movingthe port door between said input/output port and said port door storagearea.
 24. The frame as recited in claim 23, further including a housingsubstantially enclosing said port door drive mechanism.
 25. The frame asrecited in claim 24, wherein said housing is mounted to said firstelongated structural member and said housing is located between saidfirst and second end of said first elongated structural member.
 26. Theframe as recited in claim 24, wherein said housing is mounted to saidsecond elongated structural member and said housing is located betweensaid first and second end of said second elongated structural member.27. A frame of a workpiece handling tool for accessing workpieces storedin a container, the workpiece handling tool including a port door and aworkpiece handling robot, comprising: a first elongated structuralmember and a second elongated structural member, said first and secondelongated structural members each having a first end, a second end, afront face, and a rear face; a support secured to said second end ofsaid first and second elongated structural members; a port door storagearea for temporarily storing the port door, said port door storage arealocated between said front face and said rear face of said first andsecond elongated structural members; and an input/output port sized toallow a workpiece to pass through the frame between said first andsecond elongated structural members at an elevation between said firstand second ends of said first and second elongated structural members.28. The frame as recited in claim 27, wherein support comprises a singlepiece of material.
 29. The frame as recited in claim 27, wherein saidsupport comprises multiple pieces of material.
 30. The frame as recitedin claim 28, wherein said support comprises sheet metal.
 31. The frameas recited in claim 27, wherein said support includes a front componentpartially covering said front face of said first and second elongatedstructural members and a rear component partially covering said rearface of said first and second elongated structural members.
 32. Theframe as recited in claim 31, wherein said port door, while stored insaid port door storage area, is positioned between said front and rearcomponents of said support and said first and second elongatedstructural members.
 33. The frame as recited in claim 27, furtherincluding an upper support secured to said first end of said first andsecond elongated structural members.
 34. The frame as recited in claim27, further including a port door drive mechanism for moving the portdoor between said input/output port and said port door storage area. 35.The frame as recited in claim 34, further including a housingsubstantially enclosing said port door drive mechanism.
 36. The frame asrecited in claim 35, wherein said housing is mounted to said firstelongated structural member and said housing is located between saidfirst and second end of said first elongated structural member.
 37. Theframe as recited in claim 35, wherein said housing is mounted to saidsecond elongated structural member and said housing is located betweensaid first and second end of said second elongated structural member.38. A frame of a workpiece handling tool for accessing workpieces storedin a container, the workpiece handling tool including a port door and aworkpiece handling robot, comprising: a first elongated structuralmember and a second elongated structural member, said first and secondelongated structural members each having a first end, a second end, afront face, and a rear face; an upper support secured to said first endof said first and second elongated structural members; a lower supportsecured to said second end of said first and second elongated structuralmembers, said lower support having a front component partially coveringsaid front face of said first and second elongated structural membersand a rear component partially covering said rear face of said first andsecond elongated structural members; a port door storage area fortemporarily storing the port door, said port door storage area locatedbetween said front and rear components of said lower support; and aninput/output port sized to allow a workpiece to pass through the framebetween said first and second elongated structural members at anelevation between said upper support and said front component of saidlower support.
 39. The frame as recited in claim 38, wherein lowersupport comprises a single piece of material.
 40. The frame as recitedin claim 38, wherein said lower support comprises multiple pieces ofmaterial.
 41. The frame as recited in claim 39, wherein said lowersupport comprises sheet metal.
 42. The frame as recited in claim 41,wherein said port door, while stored in said port door storage area, ispositioned between said front and rear components of said lower supportand said first and second elongated structural members.
 43. The frame asrecited in claim 38, further including a port door drive mechanism formoving the port door between said input/output port and said port doorstorage area.
 44. The frame as recited in claim 43, further including ahousing substantially enclosing said port door drive mechanism.
 45. Theframe as recited in claim 44, wherein said housing is mounted to saidfirst elongated structural member and said housing is located betweensaid first and second end of said first elongated structural member. 46.The frame as recited in claim 44, wherein said housing is mounted tosaid second elongated structural member and said housing is locatedbetween said first and second end of said second elongated structuralmember.